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In a windows 7 64 bit professional, all ports seems to be blocked/closed, ping included. I shutdown windows firewall and antivirus with no luck. Searching web dosn't help either.

Any ideas on how to approach this (apart of reinstall everything

  • Use wireshark to see where the connections are dropping. You can also use netcat to set up test connections between that machine and another to confirm the issue. – jer.salamon Mar 17 '14 at 11:28
  • Opinion: it's not worth finding out if it's a one-off. If you can't burn down and replace a Windows desktop in your environment quickly you're fighting a losing battle. – Bill Weiss Mar 17 '14 at 13:23
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There could be numerous reasons why the connection is dropping: a flaky connection, driver's are having issue, viruses etc. It'll really be hard to justify the cause, you'll need to approach is in a systematic way and breaking everything down into different layers e.g. physical, datalink, application.

I have had real weird issues in the past and you can't rule out even the most simplest of things like cabling issues or physcial faults. e.g. I've once had a flaky wireless router impacting all other wireless devices. I was getting signals changing from WEP/WPA on one/two laptops, connections were getting dropped to the non-faulty router or some devices weren't able to connect to the working routers. What's unusual was the flaky router seems to functioning quite well but after disabling it, everything just worked again.

More information will be required for us to try help.

  • When did the problem occur? What tests that has been done, please post us the info?
  • Is traffic not coming in only, or is there issues with traffic coming out?
  • Have you tried running in safe mode with networking support, are you able to access the network still?
  • Does wireshark should and any traffic whatsoever?
  • The PC is on a LAN with Domain. Everything works fine except of accessing its services (namely sql server & IIS ) from other computers on the LAN. Outbound traffic has no problem at all. In safe mode with networking the behavior is the same. – PanosXY Mar 17 '14 at 14:16
  • So both firewall and antivirus had been turned-off and you're still having issues pinging? In the "Network and Sharing Center", is it still "Domain" or has it changed to "Public"? – supmethods Mar 17 '14 at 14:43
  • Is it still connected to our Domain. BTW How I can use the wireshark to investigate this? – PanosXY Mar 17 '14 at 14:53
  • Running wireshark on that PC and pinging from another, packets doesn't reach the PC. Looks like something before pcap is dropping the packages. When I run the experiment the other way around everything is normal. – PanosXY Mar 18 '14 at 4:38
  • So all firewalls has been switched off and for all networks? i.e. Windows fireeall has been disabled for domains, private and public, all third-party security software has been disabled such as firewall/antivirus/anti-walware. – supmethods Mar 18 '14 at 4:59
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Unless there is some kind of firewall you've installed (maybe somewhere between your test node and the target host, instead of on the target host?), this isn't likely worth the trouble to fix. Since this type of problem can also be caused by virus damage from an inserted filter, especially if nothing else in your environment is doing this, you should probably rebuild it.

Sometimes this can happen after security software is removed as well, for similar reasons to it happening after partial virus removal.

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